Hi

According to my research, I have to dissolve glibenclamide in DMSO to obtain a 10 mM stock solution. (I am adding it to a 10ml buffer solution in organ bath chambers for rat aorta rings). Particularly, it says that the glibenclamide is dissolved in DMSO(25mg/ml) or ethanol(5mg/ml). The final concentration of DMSO should be 0.1% for cells. 

I am confused about which percentage of DMSO should I use, 20%, 70% or pure 99.9%?

Regards